The role of hepatic Surf4 in lipoprotein metabolism and the development of atherosclerosis in apoE-/- mice

Mechanisms of METTL14-Mediated m6A Modification in Promoting Iron Overload-Induced Lipid Peroxidative Damage in Vascular Endothelial Cells to Aggravate Atherosclerosis

Atherosclerosis (AS) is a chronic multifactorial disease with damage to vascular endothelial cells (VECs). This study sought to delve into the mechanism of methyltransferase-like 14 (METTL14) in iron overload-induced lipid peroxidative damage in AS. AS mouse model and cell model were established. Levels of METTL14/circRNA coded by the Arhgap12 (circARHGAP12)/Aspartate β-hydroxylase (ASPH) were determined. AS plaque area/lipid deposition/lipid metabolism in AS mice and iron overload in VECs were evaluated. N6-methyladenosine (m6A) level and METTL14 enrichment and human antigen R (HuR) in circARHGAP12 or ASPH were measured. The mRNA stability of circARHGAP12 or ASPH was analyzed. We observed that METTL14 was upregulated in AS mice. METTL14 downregulation reduced plaque area/lipid deposition/iron overload/peroxidative damage in AS mice. In cell models, METTL14 downregulation could VEC injury/iron overload/lipid peroxidative damage. Mechanically, METTL14 increased the stability and expression of circARHGAP12 through m6A modification, further stabilized ASPH mRNA, and promoted ASPH transcription by binding to HuR. Overexpression of circARHGAP12 or inhibition of ASPH averted the protective role of METTL14 downregulation against iron overload-induced peroxidative damage in AS. In conclusion, METTL14-mediated m6A modification upregulated circARHGAP12 and ASPH to aggravate overload-induced lipid peroxidative damage and facilitate AS progression.

The link between the risk of cardiovascular diseases and the intake of different types of dietary carbohydrates in Iranian adults

Background

The risk of cardiovascular diseases (CVDs) may be influenced by dietary carbohydrates. The aim of this study was to investigate the link between CVDs and the intake of carbohydrates.

Methods

In this cross-sectional study, data was extracted from the Prospective Epidemiologic Research Studies in Iran (PERSIAN) cohort in Sabzevar, Iran. A total of 4241 adults, including 1535 patients with CVDs and 2706 people without CVDs, were included. A validated 237-item food frequency questionnaire was used to estimate the intake of different types of dietary carbohydrates.

Results

A positive association was found between stroke and dietary intake of starch (OR = 1.108; 95% CI, 1.005-1.220; P = 0.039). Additionally, a negative association was found between stroke and dietary intake of sucrose (OR = 0.97; 95%CI, 0.94-0.99; P = 0.037). No association was found between other types of CVDs and the intake of different types of carbohydrates.

Conclusion

This study provided some evidence for the association between CVDs and different types of dietary carbohydrates. Consumption of starch may increase the risk of stroke, while a higher intake of sucrose may decrease the risk of stroke. Further studies are warranted.

Hepatic Surf4 Deficiency Impairs Serum Amyloid A1 Secretion and Attenuates Liver Fibrosis in Mice

Liver fibrosis is a severe global health problem. However, no effective antifibrotic drugs have been approved. Surf4 is primarily located in the endoplasmic reticulum (ER) and mediates the transport of secreted proteins from the ER to the Golgi apparatus. Knockout of hepatic Surf4 (Surf4 LKO) in mice impairs very-low-density lipoprotein secretion without causing overt liver damage. Here, we found that collagen levels are significantly reduced in the liver of Surf4 LKO mice compared with control Surf4 flox mice, as demonstrated by proteomics, Western blot, and quantitative reverse transcription polymerase chain reaction. Therefore, this study aims to investigate whether and how hepatic Surf4 affects liver fibrosis. We observed that CCl4-induced liver fibrosis is significantly lower in Surf4 LKO mice than in Surf4 flox mice. Mechanistically, hepatic Surf4 deficiency reduces serum amyloid A1 (SAA1) secretion and hepatic stellate cell (HSC) activation. Surf4 coimmunoprecipitates and colocalizes with SAA1. Lack of hepatic Surf4 significantly reduces SAA1 secretion from hepatocytes, and SAA1 activates cultured human HSCs (LX-2 cells). Conditioned medium (CM) from Surf4-deficient primary hepatocytes activates LX-2 cells to a much lesser extent than CM from Surf4 flox primary hepatocytes, and this reduced effect is restored by the addition of recombinant SAA1 to CM from Surf4-deficient hepatocytes. Knockdown of SAA1 in primary hepatocytes or TLR2 in LX-2 cells significantly reduces LX-2 activation induced by CM from Surf4 flox hepatocytes but not from Surf4 LKO hepatocytes. Furthermore, knockdown of SAA1 significantly ameliorates liver fibrosis in Surf4 flox mice but does not further reduce liver fibrosis in Surf4 LKO mice. We also observe substantial expression of Surf4 and SAA1 in human fibrotic livers. Therefore, hepatic Surf4 facilitates SAA1 secretion, activates HSCs, and aggravates liver fibrosis, suggesting that hepatic Surf4 and SAA1 may serve as treatment targets for liver fibrosis.

Higher systemic inflammation response index is associated with increased risk of heart failure in adults: An observational study

Inflammation has been established to play a crucial role in the onset of heart failure (HF) for many years, and the systemic inflammation response index (SIRI) is a new and comprehensive indicator reflecting the inflammation status in human body. The aim of this investigation was to determine the potential relationship between HF and SIRI in adults. For this investigation, we used cross-sectional data from the National Health and Nutrition Examination Survey (NHANES), which was conducted from 2009 to 2018. The study utilized multivariable linear regression models to examine the potential independent relationship between HF and SIRI. Additionally, a subgroup analysis and interaction test were carried out. To illustrate the nonlinear relationship, threshold effect analysis and fitted smoothing curves were also used. 26,303 eligible subjects aged ≥ 20 years were enrolled as the final samples. HF participants exhibited significant higher SIRI compared with non-HF participants [1.89 ± 1.33 vs 1.25 ± 0.95 (1000 cells/μL), P < .0001]. Multivariate logistic regression showed that those in the highest SIRI quartile had a significantly greater risk of HF by 130% (OR = 2.30, 95% CI 1.41-3.76; P < .0001). In addition, nonlinear relationship between HF and SIRI with the inflection point of 2.2 (1000 cells/μL) was observed. According to our research, adult HF prevalence and SIRI are positively correlated. This implies that SIRI could be a valuable biomarker for determining HF risk in the clinic.

VLDL Biogenesis and Secretion: It Takes a Village

The production and secretion of VLDLs (very-low-density lipoproteins) by hepatocytes has a direct impact on liver fat content, as well as the concentrations of cholesterol and triglycerides in the circulation and thus affects both liver and cardiovascular health, respectively. Importantly, insulin resistance, excess caloric intake, and lack of physical activity are associated with overproduction of VLDL, hepatic steatosis, and increased plasma levels of atherogenic lipoproteins. Cholesterol and triglycerides in remnant particles generated by VLDL lipolysis are risk factors for atherosclerotic cardiovascular disease and have garnered increasing attention over the last few decades. Presently, however, increased risk of atherosclerosis is not the only concern when considering today's cardiometabolic patients, as they often also experience hepatic steatosis, a prevalent disorder that can progress to steatohepatitis and cirrhosis. This duality of metabolic risk highlights the importance of understanding the molecular regulation of the biogenesis of VLDL, the lipoprotein that transports triglycerides and cholesterol out of the liver. Fortunately, there has been a resurgence of interest in the intracellular assembly, trafficking, degradation, and secretion of VLDL by hepatocytes, which has led to many exciting new molecular insights that are the topic of this review. Increasing our understanding of the biology of this pathway will aid to the identification of novel therapeutic targets to improve both the cardiovascular and the hepatic health of cardiometabolic patients. This review focuses, for the first time, on this duality.

Discovery of a novel, liver-targeted thyroid hormone receptor-β agonist, CS271011, in the treatment of lipid metabolism disorders

INTRODUCTION

Thyroid hormone receptor β (THR-β) plays a critical role in metabolism regulation and has become an attractive target for treating lipid metabolism disorders in recent years. Thus, in this study, we discovered CS271011, a novel THR-β agonist, and assessed the safety and efficiency of CS271011 compared to MGL-3196 in vitro and in vivo.

METHODS

We conducted luciferase reporter gene assays to assess the activation of THR-β and α in vitro. C57BL/6J mice were fed a high-fat diet for 12 weeks, CS271011 was administered by gavage at the dose of 1 mg/kg and 3 mg/kg, and MGL-3196 was administered at the dose of 3 mg/kg for 10 weeks. Body weight, food intake, serum and hepatic parameters, histological analysis, pharmacokinetic studies, RNA sequencing of the liver and heart, and expression of hepatic lipid-metabolic genes were determined to evaluate the safety and efficiency of CS271011.

RESULTS

Compared with MGL-3196, CS271011 showed higher THR-β activation in vitro. In the diet-induced obesity mice model, CS271011 demonstrated favourable pharmacokinetic properties in mice and was enriched in the liver. Finally, CS271011 improved dyslipidaemia and reduced liver steatosis in the diet-induced obesity murine model. Mechanistically, CS271011 and MGL-3196 showed potent regulation of lipid metabolism-related genes.

CONCLUSIONS

CS271011 is a potent and liver-targeted THR-β agonist for treating lipid metabolism disorders.